A so-called vidicon using a photoconductive thin film has been put into practical use as a television camera tube. Studies have been extensively made to improve the characteristics of such photoconductive thin films. Furthermore, improvements in an electrode system including an electron gun have been under investigation. Useful application of vidicons have broadened to uses such as camera tubes for image-information due to the simple constitution and easy handling of vidicons.
An amorphous silicon thin film can be converted into either a p-type semiconductor or a n-type semiconductor by doping it with an impurity, these making it useful as a solar battery. This amorphous silicon thin film is advantageous due to it strong light absorption in the visible region, its high efficiency in the formation of good light carriers. Furthermore, it is a uniform thin film having a large surface area which can be easily produced. It is thus believed to be suitable as a photoelectric transfer material for photoimage recording.
Recently, a television camera tube using an amorphous thin film has been developed, but it has not yet succeeded in providing a sharp image [Cf. The 12th Conference on Solid State Devices (Tokyo) 1980, Page 97 et seq].